Porpoises Returning to SF Bay

Here’s some happy New Year news for you: harbor porpoises are once again swimming in San Francisco Bay.

According to this NPR report, the porpoises were common in the bay through the 1930s. Researchers at San Francisco State believe the introduction of war ships, the placement of a huge net across the Golden Gate (to keep out Japanese submarines) and the planting of mines (outside the Golden Gate) during WWII — plus a sharp decline in water quality in the 1950s and 1960s — drove the marine mammals away.

But as water quality has improved — and the food web has filled in again – the species seems to have rediscovered the bay. Researchers have identified about 250 individual harbor porpoises there and it looks like one good place to spot them is Golden Gate Bridge. I myself will be keeping an eye out for them from the Golden Gate’s littlest sister bridge: the Bay Farm bike bridge.